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The first steps.

Posted by Jonas on April 11, 2009 at 6:57am
Well today I am verry close finishing my first plane with a autopilot.So it is time for some contribution to this fantastic site.First I like to thank Chris Anderson and Jordi for all the effort they made!!I really like what you have done so far!!!
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glad to find the net page

Posted by yuanzhenzong on April 11, 2009 at 12:59am
as an engineer worked for uav,I need variety of knowledge about the system.It includes composite material Aerodynamics,propultion,avinics,payload(op or ir sensor)and the communication.because the real enrienment of education in my country,I haven't get the valuable material about that,today find this page and find kinds of products and subsystems,thank you.
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Starting a new ground station

Posted by Kyle Corbitt on April 10, 2009 at 7:30pm
Hey everyone, I would like to take this opportunity to post a screenshot of the groundstation I've just begun work on. I haven't gotten very far in the short time I've been working on it, but my goal is to release it around the same time as the upcoming ArduPilot Pro, which should have the ability to use a two-way digital radio for control. That gives me a good chunk of time for development and tuning.

I've put more time into playing around with different layouts than anything else so far, and I think I've settled on one that seems servicable. I would greatly appreciate it though if other community members (particularly those involved with ArduPilot Pro development) could let me know what you think of the direction I'm going... it would be much better to know sooner than later if I'm barking up the wrong tree!I should also mention that currently the "File" menu is set up as follows:"Load MissionSave Mission-------------Import KMLExport KML-------------Load PlaybackSave Playback-------------Exit"(there is nothing under "Settings" yet)Finally, for anyone interested in the code itself, I've been developing in Python using wxPython for the GUI elements.
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Ardupilot RF Interference?

Posted by Roy Stevens on April 10, 2009 at 3:21pm
I've been having some problems intermittently with RF interference when flying my Nexstar EP. I always thought it was just some local interference which kicked on and off for whatever reason and that I needed to just do a range test before each flight.However, just today I decided to try a range test with & without Ardupilot installed. With Ardupilot I could only go about 200 feet away before i started getting pretty significant twitching of the servos. Without Ardupilot everything was still rock solid at 200+ feet. So it looks like the jumble of wires I had inside before won't work... are there any special precautions I can take besides just organizing wires and keeping Ardupilot as far from the receiver as possible? Is it important to keep Ardupilot away from the ESC as well? Does anyone have any home-made RF shield ideas?I also want to thank Chris & Jordi for making Ardupilot - not only a great autopilot but a really great place for beginners to start learning.
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A bored teen's project:

Posted by Robert Drone on April 10, 2009 at 8:00am
Hi, I'm a bored teen living in south Georgia; so how's that different from any other teen? Well, I'm bored because what they teach us n school here is stuff I've known for a long time for the most part sooo I was looking around at airplanes online thinking about building a UAV and I came across this site after a while I got permission from my parents to use this site and here I am. I just posted some pictures of my custom airframe I am building and some electronics gear I could hack. I am a noob to real rc models (you know brushless motors and servos and stuff) the only real experience I have is the lego robotics system and messing with junked electonics and stuff. I was wondering if any one could answer the following questions:1. Has anyone launched an NXT or RCX using an all electric aircraft?2.Should I use the monster-truck rc unit to save money or buy a new one?(it is old so it is not proportional)3.Do you have to use a brushless and brand new battery?(could I use the one pictured)4.Could I build a magnetic sensor for the rcx or nxt?5. Does anyone have any comments questions or ideas for me?Here is a link to my pictures:

for some reason it stopped working so here is the page:http://www.diydrones.com/photo/photo/listForContributor?screenName=2le2rve18t2rmThanks,-Robert Drone:)
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LocoSys LS20031 GPS upgrade to 10Hz

Posted by Reto on April 10, 2009 at 2:18am
08975-03-L_i_ma.jpgI had some regular e-mail contact with LocoSys since I bought my 5Hz LS20031 GPS board from Sparkfun.LocoSys informed me that in June or July, they are going to propose an upgrade applicable to the LS20031. The GPS will then be able to have a 10Hz update rate.I'll post more information when available. in the meantime, here's the latest LocoSys product table for those interested: 2009DM.pdf
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Xbee socket board

Posted by Reto on April 10, 2009 at 1:00am
XBeeBreakout-01-L_i_ma.jpgWhile testing my setup, it often disturbed me that the Xbee Pro doesn't have a led somewhere to show it's powered up.Since I mount it onto a ply through an Xbee breakout board like the one on the picture, I just soldered a small red led between the VCC and GND. Now I know when it's powered ok without having to setup all Xbee transmission line.Of course, the led doesn't tell me if the Xbee is transmitting/receiving.
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To relax from programing, assembling, building, soldering, and tweaking (and maybe repairing): nice aerial videos

Posted by Reto on April 9, 2009 at 2:25pm
Not to make publicity here, but a young guy I came to correspond with is running an FPV stuff online shop (RC-Tech in Switzerland). He practices himself, of course, is very much involved in the FPV community, and, over that, has some real good sense for bringing up nice aerial video footage mostly based on the RF video material he's selling.On the web site, he's got some very enjoyable footage (in my opinion). It's a nice place to relax a bit from our UAVs developments. I am sure you'll enjoy most of them. There are some real plane videos too which are good, especially the Extra 300 flight with many different airborne camera views. The FPV comes mostly from page 2 on.Foamy slow flyers, watch that one: "Low And Slow"... crazy tree slalomingEasyGlider fans, look here.Esky Belt-CP carbon edition heli and screaming guitar solos, watch this one.There's even food for the X-Twinners... micro FPV!I'm sure there will be at least one interested in this alpine scenery of Crans-Montana or this other in Les Diablerets with the Altus XL.Finally some town night flying (but who wants to hide between parked cars at night with a black hood on his head to cover an alien video google?!?). Well, I was young some time ago, too...I wish all a enjoyable watching, a nice Easter (for those concerned), and everybody a fine week-end.
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Things are moving forward!

Posted by Tom Yochum on April 9, 2009 at 9:08am
Brian and I are moving forward at a good pace. As he wrote in his blog, we have our processor board in hand and the IMU is on its way. Yeah!I have been busy with a few tasks:1. Aircraft selection.I am pretty set on buying the AXN Floater Jet. It is inexpensive, durable (foam construction with pusher prop), and comes with aileron control. I will probably put in the order this weekend unless there are objections from Brian.2. AHRS developmentWe would like to use our IMU as the basis for an AHRS (attitude-heading reference system). An AHRS is basically an inertial navigator without the position information. To get this to work I first need an alignment algorithm. The IMU would need to be stationary while the accelerometers and gyros make measurements. The accelerometers sense the gravity vector, and this information is used to determine the pitch and roll. The gyros measure the earth's rotation and, with the help of the pitch and roll information, determine the heading relative to true north. I understand the theory, but I haven't worked out the math yet. It should be a fun problem!Once the AHRS is aligned, the accelerometer and gyro data is continuously integrated using the strapdown equations to provide the orientation of the aircraft. I have much of the AHRS code written already from a previous project. If it works remains to be seen! :-)3. Simulation developmentI did some searching and found a wonderful resource: Aerosim blockset for Simulink. It is free for educational and non-profit users. It has all the 6-DOF equations, aerodynamic equations, environmental equations, etc, for modeling an aircraft. Yeah!Now I need to get all the information about the aircraft we purchase into this model. Well, once we order an aircraft. There are a few parameters that I'm not sure how to estimate. Does anyone have a good way of estimating the moments of inertia of an RC aircraft? Also, I could use some help modeling the engine (power consumption, torque, rotation speed, etc).Once we have a simulation we can begin control law development. I am hoping to use modern control with full-state feedback. We'll see how that goes once we get there.Another feature that Brian and I would like to implement is hardware-in-the-loop simulations using Simulink. However, I don't have the Simulink add-ons for the communication. Does anyone know of some free/inexpensive software that does this?I should get back to my "real" job. As always, advice and feedback is greatly appreciated!Tom
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Platform progress

Posted by Brian Hudson on April 8, 2009 at 11:51pm
Tom and I have made a couple of decisions and are moving forward."I would not be just a nothin' my head all full of stuffin'...If I only had a brain."I purchased and have received a standard Arduino Duemilanove board. I strongly considered the ArduPilot, but I wanted to get up an running quickly and I didn't really want to spend the money for an FTDI Serial / USB cable. I've been doing some basic bootstrapping to get a few things up and running.- A simple echo terminal program as my first "hello world" type sketch- A "random" number generator set up to send data to a terminal program on the PC- A C# program to plot the data received from the number generator. Which brings me to my first request for advice / feedback in this post:Does anyone have recommendations for a set of plotting / graphing tools? Tom has a student copy of MatLab / Simulink, so I was thinking about seeing what could be done there, but I want something we can both use without me having to try to find time on his computer. I've considered Processing, but I don't really see a way to interface it easily with other software packages, and while I can't sum up succinctly why, it just doesn't seem like a language I want to invest much in. For now I've just used a free-ware copy of something called PlotLab - http://www.mitov.com/html/plotlab.html. The docs aren't very good, and it doesn't seem all that well suited to my current task, but it lets me get something on the screen quickly in a nice friendly C# .Net rapid development setup. It has some cool zoom features as well.The last thing I've written is a little quick and dirty benchmark sketch for floating point operations. I was just trying to get a ballpark here, but I can't recall where I placed the data. Either way, this wasn't very scientific. If folks have data about the efficiency of the floating point emulation sitting around somewhere, I've done some searching and haven't found much. Otherwise, this could be the topic of its own short post, although I'm by no means an expert in this area.Moving along...Input! More Input!Just today I placed the order for an Atomic IMU 6DOF sensor assembly. This was a relatively big purchase for us, but the combination of sensors set up according to manufacturer recommendation, a great little form factor package, and a programmable AVR core seemed to really fit our needs.Under ConstructionThis brings me to my next planned task - I will be writing a simple software-serial pass-thru sketch so that I can hook up the Atomic IMU 6DOF to a terminal program on the PC, play with it, and chart the output at least as a simple benchmarking / verification setup (remember I was too cheap to buy the FTDI serial / usb cable).Following that, I think my next (larger) task will be designing a serial communication protocol between the main Arduino board and the Arduino on the 6DOF. I don't want to reinvent the wheel here, so once I spec what my requirements are, I'll be hunting around for something I can base my protocol on. Here are some characteristics that come to mind, but I'm definitely not saying these are exhaustive or all necessary - obviously some are mutually exclusive, and I have some decisions to make between them:1) High speed - I want to be able to pull data at as high a frequency as our processing / navigation model needs.2) Low latency - pull model - the main controller requests data, and it gets it fast. If we're sampling very frequently, I don't want latency to indroduce complexity or inconsistency into our control / feedback model. I haven't yet quantified this at all.3) Low encoding overhead cost (the pull model kind of pushes against this goal, as there's more back and forth than perhaps necessary)4) Simple and consistent frequency samples - push model - the IMU pushes data at a consistent interval. I like the simplicity of this, but I don't want to burden the main controller with servicing and throwing away serial data that it's not going to use, wasting precious cycles.5) Flexible and extensible - Right now, I'll be using this to pull raw data straight from the sensors, either with a push or a pull model. If I go with the pull model, in order to achieve low latency I'll want some sort of request batching and transmission mechanism, which I would want to lend itself well to future expansion of the data supported. This may all be overkill, and I might just end up defining a set of metrics on both sides that grows as my needs grow.Once I've got an idea of my data transfer system, another need I'll have is the ability to program the AVR on the 6DOF. I've got a couple important issues here, in priority order:1) Fail-safe, Fail-safe, Fail-safe. I'm a bit nervous about programming an SMD chip on a $125 part. I've never programmed an Atmel before (ok fine, I've programmed my Arduino several times now, but that hardly counts). My previous experience was with the PIC microcontrollers that took minutes to program and 20 minutes in a UV light box to "erase," so my guess is that ICSP is going to be a welcome change - I sure hope so, as I have no desire to screw this baby up and get my first shot at SMD soldering with my nearly non-existent soldering tools, and very limited soldering skills. Words of encouragement and "you can't break it by flashing it, I swear!" are definitely appreciated here.2) I'm cheap :) I'm not about to drop $20+ for an AVR programmer when I've got a 16Mhz amazingly programmable physical computing platform right in front of me! I've seen far more Arduino AVR programmer set ups than I expected to when I came up with this idea and did a search, so I'd love feedback about experience folks have here if any. What sketch program did you use? What software did you use with it? My Duemilanove has the ATMega328, so I'll need something current, I think.I'm hoping Tom will be writing a post similar to this about our progress on our choice of plane. Our ever current theme of getting the most for our money has led to a fairly involved spreadsheet with our candidate airframes, their characteristics, and the cost of all the equipment to get them up and running:

Thanks to Chris for the tip on fixing up this image so you can click it for a larger version. I have links to all the parts in the cells of the spreadsheet, but obviously they're too long to make fully visible, so folks looking at the image don't know what the dollar amounts translate into in terms of parts, but like I said - hopefully Tom will post on this later!
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3D Robotics

A near tragic ArduPilot story, saved by Xbee (and GPS)!

Posted by Chris Anderson on April 8, 2009 at 10:30pm
Jordi's been doing lots of test flights of ArduPilot 2.1 and 2.2 in preparation for the Sparkfun autonomous vehicle contest. These new versions of ArduPilot include throttle control to help it handle wind better. Today seemed like a good day to test that. Jordi describes what happened: "Today i went to test my ArduPilor and winds were about 15mph with gusts of 25mph, EasyStar was having a difficult flight due to the high winds, and suddenly the EasyStar climb for about 200 meters and start drifting away from launch pad (maybe at that altitude the currents were a lot more stronger).... It was cloudy and I lost it in the sky and i was looking on the ground station how ArduPilot was trying to fighting against the wind, but the motor was almost off because the autopilot was trying to go down, but unable to travel forward, was going left and right, against the wind.... I tried to spot it on the sky over and over again to retake control, also looking into the ground station to know the direction but nothing! at that moment it was around 400 meters high!

In a matter of seconds the last position i got was 2500 meters away!! at 50 meters altitude, then i lost signal!! So i quickly took the coordinates and i made the calculation of the crash site (you know, with the last altitude and the heading i can estimate more or less the crash area, the battery was drained so no thrust at all). I've put the coordinates in motionX (iPhone app) and i begun the searching deep into the mountains!

The easystar was suposed to be lost, forever!!! And i was impressed with the range of the modem, normally i lost signal at 500 meters! Then when i spotted i could't believe it!!

And OMG i still don't know how i find it, that was horrible, hills and canyon... That was for sure luck...

Jordi"
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T3

Some Tracks and Video

Posted by Rory Paul on April 7, 2009 at 7:30pm
Flight 070409, Duration 15 minutes, winds gusting South to NorthBelow is a track in Google Earth of a recent flight....doing some modification testing on the airframe and some tweaking of the autopilot. Flight was "slightly" above AMA guidelines but as I had the field to myself for the afternoon I took the liberty.

Here is a video of the flight. The footage is boring so I sped it up.(about 45mb)...BigBird_At_CIC.wmvHere is a montage of the field. Due to gusting winds it does not match up well. I am waiting for a calm morning to take some good shots.

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RC tips: how to use flaperon with FMA Co-Pilot CPD4

Posted by Roberto on April 7, 2009 at 3:39am
When you use FMA Co-Pilot CPD4 on a plane with 2 servos on wing (one for airelon) usually you must connect an Y cable to use correctly CPD4 stabilization.With this configuration you cant use the flaperon mix (it move the 2 wing servo to the same direction to simulate flap).My idea is to use a V-Tail hardware mixer (it cost under 10$) to use flaperons.This is the connection schema:

The V-Tail mixer output will be connected to servos, the ELEVATOR input is our flap, i suggest to connect to gear channel, the RUDDER input is the airelon input, you must connect to airelon output of CPD4.Check on the trasmitter that on gear switch off all 2 airelon are on neutral posizition, then set the position on the gear switch on.I hope that my explanation is clear.
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has anyone used this rcats ??

Posted by TESTPILOT on April 7, 2009 at 1:00am

http://www.rcatsystems.com/telemetry/telemetry_uav.phpFeatures:SENSORS- Airspeed (IAS) 10-290mph- Altitude (~8ft resolution)- RPM (200 - 40,000 RPM)- Temperature (2 measurements)- Ambient temperature- Voltage measurement (0-30V)OPTIONAL SENSORS- Accelerometer- Current- Secondary voltage- Remote ambient temperature- Fuel level- GPSSOFTWARE- Live display- Data recording (via laptop) orGPS datalogger- Data Playback- Selectable VNE & Stall alarms- Rate of Climb
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3D Robotics

UAVs launching UAVs

Posted by Chris Anderson on April 6, 2009 at 5:55pm
From the description: "MADS (Miniature Aircraft Deployment System) is an Aerospace Engineering senior design project at the University of Colorado at Boulder. The mission of MADS is to deploy flight-capable, autonomous, miniature aircraft (the SuperFly) from a larger unmanned aerial vehicle (the Sig Rascal 110). Visit http://recuv.colorado.edu/MADS/ for more information!" (Actually the aircraft that are launched aren't really UAVs, since they're not guided or even controlled. And it's not clear why this team took eight months to figure out how to drop something from a plane. But it's a cool concept at least...)
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3D Robotics

PicoPilot stripdown

Posted by Chris Anderson on April 5, 2009 at 1:30pm

After stripping down AttoPilot, I thought it would be fun to compare it with the last-gen consumer autopilot, the PicoPilot NAT. There's quite a difference! The most obvious contrast is how simple and basic the PicoPilot board is. It doesn't have any of the dataline protection and noise reduction features of AttoPilot, and the PCB layout itself is hobby-grade (no effort to extend the ground planes to fill all available space, which is the trick good designers use to cut down on RF noise). No wonder it tends to need servo signal amplifiers. There's also no provision for expansion (spare pins broken out, etc). U-Nav ground off all the identifying numbers on the microprocessor and support ICs, but I've identified what I could in these photographs. (click on the pictures of the board tops to go to Flickr, where you can mouse over and see what parts I could identify) There are two boards + a GPS module. One board is the wing-leveler and GPS navigation (PicoPilot NA); the other is the altitude hold board with a pressure sensor (ALT3E). The GPS module is a stand-alone component (A Holux GR-213 module with a SiRFIII chipset). PicoPilot NA top: PicoPilot NA board top PicoPilot NA bottom: PicoPilot NA board bottom ALT3E top: PicoPilot ALT3E board top ALT3E bottom: PicoPilot ALT3E board bottom GPS module outside (this is just a standard Holux GPS module): PicoPilot GPS module The Holux GPS module inside: PicoPilot GPS module inside To give you an idea how basic these PCBs are, here's the PicoPilot bottom and the AttoPilot and ArduPilot bottoms side by side, ranked in increasing sophistication. Again, note the careful effort to maximize the ground planes (big light green areas) for noise reduction in ArduPilot and AttoPilot, and the minimal use in PicoPilot. PicoPilot PCB bottom: PicoPilot NA board bottom ArduPilot PCB bottom: ArduPilot bottom AttoPilot PCB bottom: AttoPilot board bottom
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